This application relates to an airfoil utilized in a gas turbine engine component.
Gas turbine engines typically include a plurality of sections mounted in series. A fan may deliver air to a compressor section. The compressor section compresses that air and delivers it into a combustion section at which it is mixed with fuel and combusted. Products of this combustion pass downstream over turbine rotors, and through turbine vanes. The rotors are driven to rotate by the products of combustion. Typically, the vanes include airfoils fixed between opposed radially inward and radially outward end walls. Since the vanes are mounted in the path of the products of combustion, they are subject to extremely high temperature. Thus, cooling air is typically delivered within the airfoil, and circulated to various locations on the skin of the vanes. One location to which the cooling air is directed is through a so-called showerhead array of cooling holes on a leading edge of the airfoil.
Typically, the airfoil merges into the end walls with only a very small radius of curvature, or fillet. Thus, the connection of the airfoil into the end wall could be approximated as less than 5% of the radial span of the airfoil. In such components, a flow field phenomenon known as a “bow wake” occurs wherein air has a negative pressure gradient. The gradient transports hot mid span gases onto the end wall. To address the bow wake, additional cooling holes have been formed in the end wall.
Another type of airfoil has a so-called “large fillet,” or curve, merging the airfoil into the end walls. As an example, the large fillet would extend over more than 5% of the radial length of the airfoil. With such an airfoil, the effect of bow wake is reduced or eliminated. The known large fillet airfoils have typically included a showerhead that extends through the radial extent of the airfoil.